The present invention relates to a semiconductor device, for example, a technology which can be applied to a semiconductor device having a capacitor.
A capacitor is an electronic device which accumulates charge and is used in, for example, DRAM (Dynamic Random Access Memory). There is a case where a large capacitance is required for the capacitor. The capacitance of the capacitor becomes larger as the surface area of the capacitor increases. Therefore, to obtain a capacitor having a large capacitance, the surface area of the capacitor may be made large.
Meanwhile, it is now desired that the area of a semiconductor chip should be small. To form a capacitor in this semiconductor chip, the planar shape of the capacitor must be made small. Then, as described in, for example, Patent Documents 1 to 5, at present, a capacitor may be formed in the recessed part of a wiring layer. This capacitor can obtain a large surface area with the inner side surface of the recessed part and have a small planar shape.
The above capacitor has two electrodes sandwiching a capacitance insulating film. One (for example, an upper electrode in the case of a capacitor formed by using the above recessed part) of the two electrodes may be electrically coupled to a ground potential. When the capacitor is covered with an insulating film (for example, an interlayer insulating film) in this case, coupling holes must be formed in this insulating film. There is a case where the electrode in contact with the lower ends of the coupling holes of the capacitor electrically floats when the coupling holes are formed.
Patent Document 6 teaches that the electrode which is electrically floating may be charged by reactive ion etching (RIE) when the coupling holes are formed. In this case, an electric field is produced by the above charge between the two electrodes sandwiching the capacitance insulating film. The Patent Document 6 discloses that the pressure resistance of the capacitance insulating film may be reduced by this electric field. Then, the Patent Document 6 teaches that ultraviolet light is applied to the bottoms of the coupling holes. The Patent Document 6 also teaches that an electron accumulated in this electrode is removed by ultraviolet light even when the electrically floating electrode is charged as described above.